1. Field of the Present Disclosure
The present disclosure is generally directed to a method for purifying total nucleic acids, including DNA and RNA, from specimens such as, e.g., human specimens and environmental samples. Examples of human specimens include, for example purposes only, stool, tissue, urine, and other specimens. Examples of environmental samples include, for example purposes only, water, soil, and other samples. The present disclosure is also applicable to agricultural, veterinary, food, and any other sample from which total nucleic acids samples may be extracted. The present disclosure is more specifically directed to a novel collection of materials and a procedure for use thereof.
2. Related Art
Human stool specimens are typically used in clinical laboratories to diagnose a number of diseases, including colorectal cancer and viral, bacterial, and protozoan infection. In all, it is estimated that over 6.1 million in vitro diagnostic (IVD) tests are performed on stool specimens annually in the United States. Most of these tests use mature technologies such as direct microscopic examination, culture, or immunoassays. However, a growing number of infectious agents, including adenovirus, enterovirus, norovirus, rotavirus, E. coli, and C. difficile, are now identified using molecular methods.
Stool is a complicated matrix that contains a number of proteins, polysaccharides, and small molecules that inhibit the PCR assay at the heart of most molecular assays. Therefore, laboratory staff must isolate the DNA and/or RNA content of a stool specimen prior to molecular analysis. Several commercial products for DNA extraction from stool exist. The most popular of these is the QIAamp Stool DNA Mini Kit, manufactured by Qiagen. This product requires users to process stool specimens through several steps of cell lysis, inhibitor adsorption, and protein digestion before collecting and cleaning the final DNA isolate using a microcentrifuge spin column. The resulting DNA is suitable for most applications. However, the extraction process is long, complicated, and increases the risk of sample cross-contamination. Another alternative is the use of automated DNA extraction instruments, such as the MagNA Pure line of instruments manufactured by Roche Applied Science. However, these instruments require substantial capital investment and additional pre-processing steps for use with stool.
Accordingly, there exists a pressing need for purifying DNA and/or RNA from specimens that is at least one of quicker, less complicated, has reduced capital investment, and requires fewer pre-processing steps.